Engine timing device



Jan. 3L 1950 A. B. RAUscHER ENGINE TIMING DEVICE Filed Jan. 8, 1945 N VEN TOR.

4455A? n?. ew/Jaffa? 4770/? fL/f UEE Patented Jan. 31, 1950 ypeller :of the aircraft, fand .th-us. saves.-:ar great :deal of time and labor, since.certain. .parts :of :a propeller-must be carefully. cleaned beforezreassembling Other objects-willbe apparentfrcm the following description of apreferredffem-bodiment of the invention shown in the accompanying drawings, wherein z Fig. 1 is an elevationfofthe device showin-g vthe timing plate andcthegpointerx or needle, the

latter being shown swung out of its normal vertical position;

Fig. 2 is a sectional view of the device showing in dash lines a propeller hub on which the device is mounted.

Referring particularly to the drawings, the preferred form of timing device consists of a back plate or support 5 having means for securing it to a propeller hub, a timing plate 6 secured in front of the back plat-e and provided with one or more scales, and a pointer I swingably mounted in fro-nt of the timing plate and adapted to give readings on said scales as will be described. The back plate may be a circular metal or other rigid plate and may have three or more channel members 8 fixed to the back face and each extending radially from the center and providing T-slots in which the right angularly bent ends 9a of arms 9 may slide. Arms 9 are adapted to embrace the propeller hub I0, and a iiexible strap II may be secured to one or more of the arms and may be wrapped around the remaining arms and the hub and secured, as by a buckle I2, so that the back plate will be non-rotatably held on the hub. Wing nuts I3 threaded on studs I4 projecting from the bent arm ends 9a may be tightened against the channel members 8 to clamp the arms in adjusted positions radially of the back plate. Thus the back plate is held rigidly at right angles to the axis of the hub and substantially centered relative to the same, thereby providing a desirable support for the pointer and timing plate by which readings are taken.

At the center of the back plate a hole I5 is drilled to receive a bolt IB having a smooth shank .threadedfend jportion .1 I9. zThe f smooth portion I'I ts snugly in holefl, while-thethreaded portion I8 ts in a central bore21i-n-the timing :plate &6. minuten .1 threaded-.on rbolti portion I8 `maires -itgposs'ible .to. tighten the? timinglplate on :thesback-,plate :The neeessaryfwashers, not designated by reference.'nurnerals, may :alsof-be ,.used. .The gpointer :or needle il :.ls rotatably .-supported yornthe zbolt f t'6,'g preferablyhavingz yball :bearing 23 ,-ttedinto ifazboregprovided half fway between its sends; said .:ball 'bearing ebeingucarried by the l#reduced:screw `threaded rportion I9. .'Anut :24

:andrlock nut f25f-secureithef .needle .ori pointer `to ifthewbolt, ,zwhi-lepermitting:A free?r swinging because :of .thevballzbearing VAaweight.. 26rmay.be1.secured by? asstud :2 'hand-nut i2 illtoconeiend: of: `.thefpointen theal other zend rbeirig:preferably-:pointed ianclfealways: being eupperrnost, ebecausecof :the weighted end, :exceptvwhen asviungabygthe operatoix :Both

ends of the pointer preferably project beyond the edges of the scale or timing plate, and a straight scribed line 29 extends centrally of the pointer from end to end. The pointer is transparent, being preferably made from a plastic such as polystyrene or methyl methacrylate, and the scribed line 29 may be lined up visually with graduations 30 on various scales marked or supported on the timing plate, thereby to give readings. The timing plate may be made of metal or a plastic, and preferably is opaque. It is shown as having six scales thereon, for six different gear reduction ratios of the propellerengine assembly. These ratios may be 1:1, 2:1, 3:2, 4:3, 16:11 and 16:9 as shown. Scales for other ratios may of course be provided. The upper half of the timing plate has three of these scales and the lower half has the other three. While the pointer always is upright, the timing plate may be inverted from the position shown in Fig. 1 by merely loosening nut 22 and turning the timing plate on the axis of bolt I6, whereupon the three lower scales will be uppermost, which will facilitate reading them. Thus the zeros of all six scales may be visually aligned with the scribed line 29 on the upright pointer, which properly fixes the position of each scale prior to using the device for checking timing of the engine.

Assuming that the device is installed on a propeller hub and that the propeller axis is horizontal, or nearly so, with the pointer vertical, or nearly so, the operator will turn the propeller manually until any selected one of the engine pistons is at'top dead center. Then the timing portion II, a threaded portion I8 and a reduced M plate is rotated to bring the zero of the proper ment of the selected piston in its cylinder may be read by referring to the proper scale.v `The.

operator, knowing what this movement'should be, or consulting tables in the event he is uninformed, will immediately detect any deviation.,

from the proper figure and can adjust the engine to correct the timing of the particular cylinder:

being tested.

It will be obvious that the device will save' a vast amount of time and labor when checking the timing of aircraft engines. Probably the device will be useful if adapted for other types of internal combustion engines.

What I claim is:

A timing device for multicylinder internal combustion engines in aircraft, said device comprising a supporting means including a vertical supporting plate having detachable members thereon to embrace andclamp the hub of an aircraft propeller, said members being adjustable on said plate and having fastening means thereon for holding them securely upon the hub in longitudinal alignment therewith whereby the device will be suitable for use on hubs of various sizes, a scale plate having selectively concentric scale indicia indicative of gear reduction ratio between the propeller and the engine marked thereon for checking the timing ofthe cylinders, each scale extending only through a half circle, means to support the scale plate upon the sup- 4 porting plate so that it is angularly adjustable relative to the latter that normally turns with the supporting plate and the hub, and a transparent pointer of greater length than a normal propeller hub diameter, said pointer being swingably mounted on said scale support, the swing axis of said pointer and plate cutting a prolongation of a longitudinal axis of the hub, a flat Weight at the lower end of said pointer and said 'pointer being hence adapted to lie in a plumb .line irrespective of movements of the scale plate and having a single indicating line on its longer axis whereby to overlie points on all of the scale indicia and so to enable the timing of the aircraft engine to be checked without removal of the propeller.

ALBERT B. RAUSCHER.

REFERENCES CITED The following references are of record in the file of this patent: y

UNITED STATES PATENTS Number Name Date 529,953 Presnell Nov. 27, 1894 888,826 Kooken May 26, 1908 1,133,540 Dannenberg Mar. 30, 1915 1,371,371 Hinsman Mar. 15, 1921 1,377,720 Neff May 10, 1921 1,742,069 Greenwald et al. Dec. 31. 1929 1,826,997 Dietrich Oct. 13, 1931 1,885,788 Westburg Nov. 1, 1932 2,104,521 Jackson et al. Jan. 4, 1938 2,438,229 Price Mar. 23, 1948 FOREIGN PATENTS Number Country Date 20,929 Great Britain of 1907 

